Switch



5, 1933. H. D. GARRETSON 1,941,081

SWITCH Filed March 28, 1953 IAN [N708 cf/arrg Garrefirow BY v ATTORN EY Patented Dec. 26, 1933 1 1,941,03 T1 jg w mn lflarry .DLCiarretson, Neyfgg-k, N, W a ti! serial .NQ- 663,144 sciain uroi. 2009-111 This invention relates to a s witc h or 1 similar means for initiating an "X-ray exposure by arcing. a current between electrical contacts. The con-.

tacts in their normal position are so shaped and spaced that the current cannot normally jump between them. When the relationship of the con- 1 tacts are changed,'by a means forming the subject matter of this invention, the'current will arc over or bridge the gap'and initiate the X-ray exposure at the desired moment. r

The object of this invention is to'provide a simple high tension switching device operative to change the sphericity of a normally spherical contact, whereby the tendency of the current to jump or are from said altered contact to aj spaced companion contact is increased, and the spark resultantly occurs at the desired time; 1 More specifically, the apparatus comprises a;

pair of definitely spaced spherical members or 9 contacts so positioned with respect to one another uses, such as for a 'hi'gh-tension switch .or the like.

In the accompanying drawing Fig. 1 diagram? matically illustrates the device as. used in an X-ray system, and Fig. 2 is a longitudinal sectional view through the switch means.

In Fig. 1 of the drawing, the usual high tension generator used in X-ray systems is shown. It comprises the high tension transformer 1, connected in the customarymanner'to the valve 2. A filament transformer 3 connects to the filament of the valve, and another filament transformer 4 connects to the filament of the X-ray tube 5. The anode 6 of the X-ray tube 5 is connected to a spherical contact member '7 spaced 7 by a fixed gap 8 from a, similar spherical conill tact 9. The sphere 9 connects to the several transformers 1, 3 and 4 in the manner shown and also to the condensers 10. r

Movable within the sphere 9 is ,astem .in the form of a rod or wire 11 adapted to have its-end projected out of the sphere into the gap 8 and toward the other sphere 7. The stem 11 is of me a a d i e ect i a a nta ith il es ere vIt is m'wes h ou h a' uide zlo si wi i thflfip l fi- T wil l 'i e u d. PWQPK of a rod 13 of fibre or other insulating material,

said 'rod'l3 being ,slidable through :a guide 14 projecting from the outside of the sphere 9. The guide 14 is surrounded by a tube 15 of insulation, which is provided at a distance from the sphere ,9 with a solenoid 16. At its lower end, the rod 13 is secured to an iron plunger 17, adapted to be drawn upwardly when the solenoid is energized. A stem 18 on the plunger 17 is guided by' an opening in the bottom 19 of the tube '15, during movement of the plunger 19 and the rods 13 and 11 carried by it.

vicewill be readily understood. The current normally will not jump the gap 8 between the. two spheres 7 and 9, it being well understood that a gap between .spherical contacts is not From the foregoing, the operation of the dereadily jumped. To cause a spark to jump between the spheres, 7 and 9, it is merely neces-- sary to'close the switch 20 connecting the solenoid with a source of current, whereupon the solenoid, being energized, will draw the plunger 17 upwardly, thrusting the stem '11 out of the. body of the sphere 9 andinto, the gap 8 and toward the other sphere 7. The outward movement of the stem 11 is; limited by a spring 21 surrounding the stem and which contacts with J th e,guide-12. Theextent'of the projection of the stem 11 outof the sphere '9 is determined by I the purpose to which the device is put. When used in an X-ray apparatus, where it'is desired to have a spark jump the gap between the two spheres, the stem need extend only partly across the gap toward the other sphere. If the device is used as a high tension" switch, the'stem may be projected fromthe switch {within which it is located, across the gap and into actual contact with the other sphere. l 1

' In using .the term sphere'herein, I intend that it' shall refer to any generally spherical member or other memberso shaped as to by its shape act to decrease the tendency of the current to jump thegap. The stem 11 movable out of one'of the spheres into the gap between the spheres acts to destroy the sphericity of the sphere out of which it moves, thus aiding the current to are or spark across the gap.- The use of spherical members on the opposite sides v of the spark gap prevents voltage losses and generally increases the efficiency of, the appara-' tus.

and an armature attached to the rod within the casing so that when the solenoid is energized the stem carried by the rod is projected out 01! the sphere toward the other sphere.

2. A device of the character prising, spaced spheres defining a spark gap between them, a stem normally held in a retarded position in one of saidspheres, said stem having a portion projecting outside of the sphere and outside of the sphere for moving the armature and stem carried thereby to shift a portion of the stem out of the sphere when the solenoid is energized.

3. A device of the character described comprising, spaced spheres carrying current and separated to such an extent as to normally prevent arcing of the current between them, a stem normally held. in, a retarded position within one of the spheres, said stem protruding from the end of a rod of insulation, the rod having a portion protruding from the sphere, a tubular insulated casing secured to and projecting from the sphere, said casing surrounding that portion of the rod which protrudes from the sphere, a solenoid surroundingand supported by the casing, and an armature secured to one end described com' of the rod within the casing, and means in the casing'for guiding the rod and armature in its movement therein.

HARRY D; GARRETSQN.

carrying an armature, and a solenoid mounted 

